Gaskets’ Construction

Gaskets used in industry is generally composed of sealing element and inner and outer rings. The sealing element also called gasket body is the key part to prevent leakage. The material for the sealing element is usually non-metallic material such as flexible graphite, PTFE, non-asbestos, etc. In addition, the material also can be rigid or soft metal which is commonly used in higher pressure and temperature environment.

As for non-metallic sealing elements, it’s usually reinforced with a metallic material to make it strong enough for some application, especially for fragile material like pure flexible graphite.

The reinforced metallic material can be thin sheet or wire, and the thin sheet is always tanged to provide better sealing and resilience force. By using a binder and rolling, the graphite can be closely sticking to the sheet. Besides, an anti-sticking agent can be applied on the surfaces of the finished sheet to provide better sealing function and avoid stick with the flange’s surface.

The inner and outer rings are always solid metal, and their functions are as below:

– Work as a center ring during installation.

– Avoid the sealing element’s damages under extra pressure.

– Avoid the gasket’s blow-out and minimize the flanges’ turns.

– The outer ring is always made of carbon steel as it’s not in contact with the sealing medium and not required to be resistant to corrosive medium. It can also be integrated with the sealing element, such as metal kammprofile or metallic grooved gaskets.

– The inner ring’s material should be considered to be corrosion resistant as it’s in contact of the sealing medium. The inner ring is to prevent the fluid flow in the gap of sealing element and container or pipe flange and the impact on gasket resulted from the fluid flow.

Gaskets types:

We classify the various gasket into three types based on the different materials:

Non-metallic gasket, semi-metallic gasket, and metallic gaskets. please see below chart:

And you can also refer to our blog: Gasket Material to have a look at the materials.

Below we are going to talk about the most commonly used gaskets in the above three types:

Type 1: Non-metallic gasket: PTFE envelope rubber Gasket

*What is PTFE envelope Gasket?

It’s a kind of non-metallic composite gaskets made up of a PTFE envelope and an insert rubber gasket. The PTFE envelope protects the insert gasket from corrosion while the insert gaskets are always made from asbestos-free jointing sheets of EPDM rubber.

The gaskets are mainly used for full-faced or raised faced flanges and suitable for the nominal pressure of PN0.6 to 5Mpa and working temperature from 0~150℃ environment with corrosive medium and medium with high requirements for cleanliness.

*What is the construction of PTFE envelope Gasket?

This flange gasket can be classified into three types base on different manufacturing methods: Fin type or called split type, M type or machined type and F type or folded type.

Type 2: Semi-metallic Gasket

• Spiral wound gasket

It is made from stainless steel strip with non-metallic tape and the formed metal steel strip works as a spring to provide better compressibility when under pressure. It is a kind of semi-metallic gasket.

Characteristics of the spiral wound gaskets:

1. Good compressibility and resilience.
2. It can provide multiple sealing.
3. Non-sticky and easy installation & easy to remove.
4. Low requirement for the flange surface’s perfectness.
5. It can partially eliminate the influence from pressure, temperature and mechanical vibration.
6. It can keep its excellent sealing performance under high temperature, low pressure, high vacuum, vibration and other severe conditions.

Construction of Spiral wound Gasket:

We provide four types of spiral wound gasket: Basic type, Spiral wound gasket with inner ring (RIR type), Spiral wound gasket with outer ring (CG type), Spiral wound gasket with inner and outer ring (CGI type).

Please refer to our blog How to choose a suitable spiral wound gasket for your flange to get more information.

Mark on the Spiral wound gasket:

• Take the picture on left as example (CGI type)
• The inner ring material is carbon steel;
• The outer ring material is 316L;
•  Winding material is 316L;
•  Filler material is Graphite;
•  Gasket size: 2”3-600#
•   Manufacturer: Ginseal
•   Gasket Standard: ASME B16.20

• Metal Jacketed Gasket:

It’s made from a thin metal jacketed with a non-metallic filler always in graphite or non-asbestos.

Commonly the thin metal jacket’s thickness is 0.25~0.5mm.

The most commonly used metal jacketed gasket is double jacketed gasket with flat surface.

• SS tanged Graphite Gasket

It’s also called SS reinforced graphite gasket which is cut from tanged graphite sheet. It is comprising two outer layers of graphite foil with a central tanged stainless steel core of 0.1mm thick. The graphite layers are mechanically pressed together and won’t be delaminated during punching, storage, and use.

This gasket has good resistance to high and low temperature, to corrosion and can work under conditions of high pressure.

Its pre-tightening force required is less than the use of metal gaskets and spiral wound gaskets. Due to the graphite’s flexibility and filling property, it’s unnecessary to precision machining on the flange’s surface while underuse, and also it’s also suitable for the flanges with waterline groove. So the tanged graphite gasket is an economical choice when comparing to other gaskets.

• Kammprofile Gasket

It’s made up of a serrated metal core with a soft material usually in graphite or PTFE.

The gasket composes of the metal’s strength and serrated elasticity and soft material’s resilience. It’s suitable for high pressure and high temperature when the soft material is graphite.

There are three types for kammprofile gasket/metal grooved gasket: Basic type, Kammprofile gasket with loose outer ring, and kammprofile gasket with an integral outer ring. Please refer to Kammprofile Gasket-Grooved Gasket to know more about it.

Type 3: Metal Gasket

• Ring Joint Gasket

It is a metallic gasket with its cross-section machined to octagonal or oval shape. It provides sealing function by contacting with the inside and outside of the flange’s groove under pressing.

Octagonal type Ring joints are a face to face seal while oval type Ring joints are line seal. Based on the different sealing way, the oval type can provide better sealability but require high machining precision and cannot be re-used which result in higher cost compared with octagonal ring type joints.

The ring joints’ recommended working pressure is 2.0~42.0Mpa.

The choice made on the gaskets:

When choosing a suitable flange gasket, we should base on below basic information:

• Flange face type and dimensions
• Nominal diameter of flange or gasket
• Nominal pressure of flange or gasket
• Temperature of the fluid
• Characteristics of the fluid

And we also need to have knowledge of below:

• If the gasket can provide good compressibility and resilience and if it can adapt to the influence of temperature and pressure.
• If the gasket flexible enough to fit well with the flange face.
• For some metal flanges sensitive to stress corrosion, the gaskets’ material shall not contain excessive impurities which will lead to various corrosion, for example, we should take a note of the content of chloride ions in the material as it will corrode the flange.
• The gaskets’ material should not contaminate the fluid media.
• For sealing highly toxic chemicals, we should request the maximum safeness from the gaskets. For sealing in the pipes carrying flammable liquids, we should consider to choose gaskets suitable for the maximum pressure and temperature.
• The gaskets should have good machining performance and easy to install.
• The gaskets should be easy to remove and no-adhesive to flange.

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Stainless Steel 904L is a kind of austenitic stainless steel with a very low content of carbon. It is specially designed for severe conditions of corrosion and originally developed for anti-corrosion in dilute sulfuric acid. 904L which is the same as other CrNi based commonly used austenitic stainless steel has good resistance to pitting corrosion, crevice corrosion and high resistance to stress corrosion cracking, intergranular corrosion. And it offers excellent processability and weldability.

Other terms for 904L according to different standards:

Key properties:

Firstly, let us see the composition of this material:

• Corrosion resistance

From the above tables, we can see 904L has 23~28% nickel and 4~5% molybdenum which provide it good chloride stress corrosion cracking resistance, pitting, and general corrosion resistance.

And by adding copper in it, 904L is resistant to sulphuric acid and other agents in both aggressive and mild conditions.

• Processability and weldability

904L can be easily processed and easily welded by most standard processes. It is quite soft and forms easily. But compared with conventional stainless steel such as 304L/304, its extra molybdenum and nitrogen means more powerful processing equipment may be required. This material does not require pre-heat and post-weld heat treatments.

When referring to hot forming, the working temperature of 850~1150℃ is recommended. And subsequent annealing is not required for most cases which is unlike other stainless steel.

But it should be solution annealed at 1060~1140℃.

Applications:

904L is a versatile material that can be used in many industrial applications:

• Petroleum and petrochemical equipment such as reactors in these types of equipment.
• Storage and transportation equipment for sulfuric acid such as heat exchangers.
• Fuel gas desulfurization device of the power plant.
• Scrubber and fan in the organic acid treatment system.
• Pulp and paper processing industries.
• Seawater cooling devices.
• Wiring in electrostatic precipitators.

Comparison of some possible alternative material:

As 904L contains high amounts of molybdenum and nickel which are really expensive, Now most of applications require 904L are replaced by another low-cost stainless steel.

S316L is an alternative material with lower cost but it is lower resistant to corrosion.

6Mo/ 254Smo/S31254 is another alternative material which can provide higher resistance to pitting and crevice corrosion.

2205/ S31803 has a similar resistance to corrosion with 904L but with higher mechanical strength while lower cost. Only take note that it’s not suitable for temperatures above 300℃.

Super duplex can provide higher corrosion resistance and higher mechanical strength compared with 904L.

The post A Complete Guide About Stainless Steel 904L appeared first on .

Sometimes metal wires will be added to strengthen the packing and make it better in anti-friction properties.

Gland packing Features:

Always the gland packing has the characteristics of anti-friction feature which will make the gland packing provide better sealing function when the shaft moves which will generate heat and friction occurs.

No chemical reaction makes the braided gland packing not collapse when seals the liquids.

Temperature resistance is to ensure the braided packing suitable for the working environment.

Resilience and comprehensibility: The gland packing will compress when it is working and receive the pressure from the flange, and then it will strengthen the shaft and return back to its original shape on the release of the tension. In this way, the gland packing will give a good sealability.

No contamination with the fluid: The gland packing should not contaminate the fluid when in some industries especially pharmaceutical and the food industry.

Non-corrosive: The gland packing should be not corroded in working conditions to prevent any damage to the shaft.

Lubricant retention: The lubricants like grease, graphite maintained with a gland packing will provide it better anti-friction properties.

Applications for Gland Packing:

Gland packings are used for sealing in below applications:

• To seal in static applications like manholes, tank hatchet.
• To reduce leakage along the stem in gate valve, ball valve and globe valves.
• To reduce leakage of the working fluid in reciprocating pumps or rotating pumps like centrifugal pumps and screw and gear pumps.
• To seal propeller shafts in lifeboats and merchants ships of older generation.

The above applications requires different gland packing material, Then it goes to the selection of gland packings. It is very important as an incorrect choice will lead to failing in service and leakage.

Selection of Gland Packing:

The gland packing is aim to seal the gap on the rotating shaft by controlling the leakage of the medium and reducing the unnecessary emission into the environment. We have four main criteria to choose the correct packing:

Operating Temperature: There should be a safe margin of the max. working temperature for the gland packing especially in the case of dynamic application. As most material’s temperature exceeds when during operation, the friction occurs and the temperature will increase accordingly which will result in overheating and burnout of machine parts. Then we can also see that the medium temperature is not the same as the packing temperature, due to the friction, gland packing works at a higher temperature. For these occasions, graphite and carbon fiber-based gland packing is a good solution. From the above description, we know it’s critical to select a proper temperature range to avoid immediate failure or leakage.

Sealing Pressure: When the gland packing is installed into the stuffing box, it is tightened and compressed between the shaft and stuffing box wall. When compressed, the packing will expand and exert a radial force against the shaft. Then friction is generated and the gland pressure is regulated to provide lubrication to seal and prevent overheating.

Shaft Speed: When a gland packing is working, the movement between the shaft and the packing will generate friction which will result in wear of the packing and the generated heat will degrade the packing’s properties. Most pumps and equipment are specified with the shaft speed to tell us the number of revolutions per minute. It is very important to know the working condition of the gland packing.

Chemical resistance: To ensure the packing won’t be corroded in the sealed fluids is crucial as corroded material will degrade gland packing’s function and lead to leakage. It is good way to choose material with full PH range of 0~14.

Except above main factors, we also need consider the gland packing’s material. As braided packing is always made of the combination of the materials and a really wide range of material can be selected.

Materials for Gland Packings:

Of a great variety of gland material in the market, we always classify them into five basic kinds:

Natural fibers, flexible graphite, PTFE, Aramid and carbon fibers. These are the most common and important combination of the braided packings. These five kinds of material have their own characteristics and are not interchangeable or replaceable for specific working conditions.

Always the gland packing will be impregnated to improve its sliding properties and heat dissipation and anti-friction. The most common lubricants / impregnates are graphite, PTFE dispersion and grease.

Natural fibers: it refers to cotton, ramie which is natural planted. The most common packing our clients get from us is ramie packing with PTFE impregnation. This packing has excellent mechanical characteristics and resistance to abrasive wear and low friction. It is good option for hygienic applications but not suitable for wide range of working temperature and easily be influenced by chemical factors. The max. working temperature is 120℃ with PH 5~9 and linear velocity is 6m/s.

Application for natural fibers packing is clean water and brine where temperature is limited and with no strong chemicals.

Flexible Graphite: It’s made into graphite yarn from flake graphite which has good thermal and chemical resistance, thermal conductivity and self-lubricating properties. Then braid the yarn to packing structure. And it’s also flexible. It is perfect packing for environment with heat shocks and overheating. The graphite provides a really good anti-friction feature and sliding characteristics. The max. operating temperature is 450℃ with PH 0-14 and linear velocity is 40m/s.

Application for graphite gland packing is dynamic centrifugal pumps for water, petroleum derivatives and other chemicals, especially under high speed and high-pressured and temperature conditions.

PTFE: With excellent chemical stability (withstand strong oxidants, ozone and acid, alkali), corrosion resistance, high lubricity, non-sticky characteristics, aging resistance and long-term service in wide range of temperature (-180℃~+250℃), low coefficient of friction, PTFE Packing offers a wide range of use in most industries.

There’re two types of PTFE-based packing: 100% pure PTFE packing (white PTFE Packing) and Graphite PTFE Packing (black PTFE packing). Pure PTFE packing is supposed to be used in hygienic applications and food industry while graphite PTFE packing is suitable for higher range of shaft pressure and speed as it has better sliding performance and heat resistance.

Apart from above two types of PTFE Packing, we also have other PTFE combined with aramid fiber packing: PTFE Packing with aramid corners, Graphite PTFE packing with aramid corners, Graphite PTFE Zebra patterned packing. These packings are braided with white / black PTFE and aramid fiber, by adding aramid fiber and graphite impregnates, the packings provide better abrasive resistance and sliding properties. They are suitable for dynamic sealing conditions with a higher linear speed and pressure. These hybrid packings composed of aramid and PTFE are used in chemical industry, oil and gas, pharmacy, electricity and equipment of centrifugal reciprocating pumps, agitators and mixers, etc.

The max. working temperature for PTFE Packing is 260℃ with PH 0~14 and linear velocity of 15m/s while 25m/s for graphite PTFE packing.

Aramid Fiber: It is a synthetic fiber with good strength and abrasion resistance, high resilience and low cold flow. It is also called artificial metallic wire due to its strength, so it easily wipes the shaft. That’s the reason we always impregnate it with PTFE or graphite emulsion and lubricants to provide a high efficiency and durability in dynamic seals.

Besides above combination packing (Aramid and PTFE), there’re aramid fiber packing which is braided with aramid /Kevlar fiber impregnated with PTFE emulsion and it provides very excellent resistance features and Aramid Spun yarn Packing which is made with discontinuous twisted yarn. The spun yarn packing is braided with each impregnated aramid yarn and then impregnate again on the packing body during the braiding.

The packings can resist more severe media and higher pressure, it is ideal end rings with other packing rings to protect entire set of packing rings from abrasive particles by reducing friction to improve service life.

The max. operating temperature is 260℃ with PH 3~12 and linear velocity is 10m/s.

Carbon fibers: It is light and durable and resistant to high temperature and abrasion. It’s a new material with excellent mechanical properties, no creep, good corrosion resistance and thermal conductivity. Carbon fiber packing is suitable seal for dynamic seal application due to its high thermal conductivity. It can instantly conduct the heat generated during the movement of the sealing material and shaft, in this way the seal environment won’t be overheated and the equipment work properly. Its low coefficient of thermal expansion makes it suitable in dynamic seal of severe conditions. The lower the coefficient of friction, the less power consumes. Which enable the carbon fiber packing be suitable for high speed dynamic seal application and longer working life due to its low abrasive resistance and high strength.

The max. working temperature is 600℃ with PH 0~14 and linear velocity is 20m/s.

Above are the basic material for braiding the gland packings, usually we can also add stainless wire like Inconel wire and silicon rubber core to provide the packings with high strength.

The most commonly used gland packings:

Despite there’re so many different materials for gland packing and different combination of the material, we can provide almost 20~30 different types of gland packing, but the most commonly used are only several types as below:

Graphite Gland Packing: It is made of pure flexible graphite yarn and it has the advantage of good self-lubricity and heat conduction, small friction coefficient, high strength and good softness which can protect the valve’s stem while under operation.

Sometimes we can add fiberglass and stainless wire or Inconel wire to strengthen the pure graphite packing and enable the packing shoulder higher pressure and higher temperature and provide a longer working life.

PTFE Gland Packing: It is braided with 100% pure PTFE yarn with on other addition to it. So it’s widely used in pumps and valves which request clean and no contamination. It is FDA approved and can be used in food and pharmacy industries.

There’s another PTFE packing which is made of stretched PTFE yarn fully impregnated with PTFE latex. It has better performance in react to pressure and a smaller friction coefficient compared with pure PTFE packing.

Graphite PTFE Packing: It is packing made of PTFE yarn impregnated with graphite emulsion. The gland packing combines the characteristics of PTFE and graphite together to make it a good packing with low friction, flexibility, heat conduction and resistance in most desirable ranges. It is suitable for dynamic sealing conditions with media flow of high linear velocity.

Aramid Gland Packing: It is braided with aramid / Kevlar fiber impregnated with PTFE and lubricating oil. It provides good resistance to chemicals, high tensile strength, low cold flow and can be used in conditions with high rotating speed.

And there’re several types of hybrid aramid packing, such as graphited PTFE packing with aramid corners, Pure PTFE packing with aramid corners, graphited PTFE packing with aramid in zebra format. These packings improve sliding properties, flexibility and heat dissipation.

Ramie PTFE Packing: It’s braided with natural ramie yarn with impregnation of PTFE and impregnate in PTFE emulsion while weaving the packing. It has good sealability, lubricating.

The packing ensures tightness under lower pressures of the gland.

How does Gland packing work?

A gland packing works as a mechanical seal but with lower cost, it is soft and flexible to be inserted into the stuffing box (a gap between the shaft and the pump housing)/ packed around the shaft. The gland packing will be compressed to form a seal to prevent any leakage of the medium when the tap of the pump is turned on. And the gland packing’s characteristics which we just mentioned above will enable the packings for longer working life and require little maintenance.

How to install the gland packing:

It’s important to install the gland packing correctly to avoid of any failures during operation.

Below are the procedures for the gland packings’ installation:

• Lockdown and close valves and relieve all pressure.
• Remove all the old gland packings from the stuffing box. Clean the stuffing box and check if it’s worn or not. Replace it if it’s worn a lot.
• Choose the right dimension of the gland packing or die-formed packing rings.
• When using coil or spiral packing, remember to cut the packings into separate rings. Do not wind, cut on the mandrel the same size as the sleeve. Hold the packing rope tightly around the mandrel and remember do not stretch it. Cut the rings and make sure it fits the packing space properly.
• Install one ring at a time. Sometimes lubricant is required inside of the stuffing box.
• Install the right numbers of the rings or correct length of the rope packings.
• After finishing all the rings’ installation, take up bolts finger tight or slightly snugged up.
• There should be an allowance for leakage freely at first and gradually tighten the gland to a certain leakage rate, which will result in a better packing job for a longer period of time.

But do not over tighten.

• Replace the packing if uncontrolled excessive leakage occurs.

Where can I buy the gland packings and how can I place gland packing orders:

We Ginseal has more than 30 years of sealing experience, we can provide a wide range of selection of gland packings.

Above mentioned packing types are all in our range, you can kindly contact our sales to get a high-quality braided gland packing at a competitive price. Our products are sold to Europe, the North of America and the South of America, Southeast Asia, the Middle East, etc.

If you are not sure about what kind of gland packing you need, we can provide our professional suggestions based on the application.

When you make an inquiry or an order, please just let us know the dimensions/cross-section of the gland packing and the material.

Dimensions / Cross-Section we usually supply: 1/8” ~3” (3x3mm ~75x75mm)

Regular Package: 2.5 kgs/roll, 5kgs/roll, 10kgs/ roll, etc.

Special dimensions or packages are also available upon request.

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A spiral wound gasket consists of a V-shaped / W shaped stainless steel strip that is wound into a spiral and non-metallic tape which separates the metal layers. And the non-metallic tape gives a good resilience and sealability. That’s why we call these type gaskets as spiral wound gasket.

Usually, a spiral wound gasket has three parts:

•   Outer ring: It’s also called a centering ring or guide ring which is made of carbon steel or other stainless steel. The outer ring is for fixing the gasket into a bolted flange joint.
•   Inner ring: It’s made of stainless steel and always the same material with the winding. And the inner ring prevents windings from bulking inside the pipes, reduces the turbulent flow of process fluids and minimizes erosion at flange faces.
•   Sealing element: It provides scalability and prevents leakages while the gaskets are in use.

Its inner and outer diameters are reinforced with several layers of the metal strip without non-metallic tape, in this way it can provide greater stability and better compression and sealing function.

When should we consider using a spiral wound gasket?

When a flat gasket cannot provide a better seal over a long time, or there’s high-temperature and high-pressure conditions and corrosive media, or the flanges are out of parallel and the gap between them varies or the gap is smaller and needs material to be compressed more, it’s time to consider a spiral wound gasket.

Why we need a spiral wound gasket?

The spiral wound gasket works well in high temperature and high-pressure environment, it can adjust for temperature changes, shock, and vibration. With compressibility and recovery, spiral wound gaskets are the best semi-metallic gasket for most flanges. They can be used in pipes, heat exchangers and even sometimes take favor over Ring Joint Gasket for high-pressure flanges.

Where do we use a spiral wound gasket?

The spiral wound gasket is always used under the high/low temperature and high/low-pressure conditions, and also used in metal-to-metal joints and have a good tolerance for flange surface finish irregularities. The spiral wounds are used to prevent any leakage of toxic fluids or corrosive media in the petrochemical industry and similar industries.

Can a spiral wound gasket be re-used?

It is not recommended to re-use a spiral wound gasket. As when a spiral wound gasket is underuse, the flange load permanently compresses the sealing element of the gasket, over time, high temperature, high pressure and the huge amount of liquids may destroy the overall structure of this part and second use of the gasket will often lead to leakage.

What is the thickness and compression of a spiral wound gasket?

According to standard, there are two thicknesses (1/8”/ 3.2mm and 3/16”/4.5mm) suitable for most applications. Compressibility and recovery make the gasket the best metallic gasket for most flanges, It’s critical to know the compression. For 1/8” thickness gaskets, compression to a thickness of 0.1000” to 0.005” is recommended while 0.130” to 0.005” for 3/16” thickness gaskets.

What are the types of spiral wound gasket?

Usually, there are four types of spiral wound gasket:

• Style CG: It is a spiral wound gasket with only an outer ring/center ring. The outer ring will center the gasket on the flange face and prevent the gasket blow-out and acts as a compression stop. This type of sealing gaskets is suitable for flat face and raised face flanges.
• Style CGI: It is a gasket with the inner and outer ring or CG type with an inner ring. Besides the advantages of CG type spiral wound gaskets, the internal ring can work as a barrier to prevent flange erosion and also act as a compression stop. It is suitable for flat face and raised face flanges.
• Style R: It is a basic type of spiral wound gasket without inner ring and outer ring and used for tongue and groove, male and female type joint of flanges.
• Style RIR: It is a gasket with only an inner ring. The inner ring prevents the accumulation of solids and works as an additional compression stop. It is suitable for male and female flanges.

The post When and Why We Need Spiral Wound Gasket appeared first on .

Profile	Products	Style	Flange	For example
	Basic type SWG	JSG-SW10	Tongue/Groove	304/F.G
	SWG with inner ring	JSG-SW40	Male and         Female	304 304/F.G
	SWG with outer ring	JSG-SW30	Raised  face          Flat face	304/ABS CS
	SWG with inner         &outer rings	JSG-SW20	Flat face and groove face and raised face	304 304/F.G CS
	SWG for heat              exchanger	JSG-SWH	Heat          exchanger	304/F.G with 1 bar of DJ      304/F.G
	Special shape SWG	JSG-SWC	Special	Track, Oval, Diamond, Square

The Choice of Spiral wound gasket:

The installation of Spiral wound gasket:

• Make sure the sealing face of gaskets and flanges clean, no scratches or spots on the sealing faces.
• The outer diameter of the gasket should be smaller than that of the flange’s sealing face while the inner diameter of gaskets should be larger than that of the pipe.
• The gasket should be installed in the center of the flange’s sealing face, especially for raised face flanges.
• Make sure of an even and symmetric force when installing the gasket to the flange. The designed force should not be achieved once, always we should screw up at least 2-3 times. In this way, the spiral wounds can provide a better sealing function.
• Check and recalibrate the torque of the connection bolts after one cycle of operation of the valves and pipes.
• Don’t use liquid-base or metal-base anti-sticking agents or lubricating agents.
• It’s a must to lower the pressure firstly and then adjust the gasket or remove it when there’s a leakage of the pipes.

The post How to Choose a Suitable Spiral Wound Gasket for Your Flange appeared first on .

Industrial Rubber

• Natural rubber is suitable for the use in water, seawater, air, inert gases, alkali, saltwater solutions, and other media, but not resistant to mineral oil and non-polar solvents. It cannot be used for a long time in the environment of temperature over 90℃, but it’s an excellent material to be used at -60℃ due to its low-temperature performance.
• NBR is suitable for petroleum industries such as petroleum, lubricating oil, fuel oil, etc. Its working temperature is 120℃ and can withstand low temperature to -10~20℃. However, when it’s used in hot oil, the max. working temperature can be 150℃.
• Neoprene Rubber is good for seawater, weak acid and alkali, salt solution. It has perfect oxygen resistance and ozone aging performance and oil resistance.

• Viton rubber has good acid resistance, oxidation resistance, oil resistance, solvent resistance. It can be used in almost all acid media as well as some oils and solvents. The working temperature is ~120℃.

PTFE Material:

Metal Jacketed Gasket:

Spiral Wound Gasket:

   When referring to medium pressure and temperature over 300℃, we should consider using spiral wound gaskets with inner rings and outer rings.

Metal Flat Gasket and Kammprofile Gasket:

Ring Joint Gasket:

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